Schorger— : Chemistry of American Conifers. 729 
pendent upon the longleaf pine and Cuban pine and the ex¬ 
haustion of these species is in sight. It has been found, how¬ 
ever, that the western yellow pine will be capable of furnishing 
naval stpres satisfactory both as to quality and quantity after 
the species in present use are exhausted. 
There are approximately 92 species of conifers in the United 
States. From each species there is a possibility of obtaining 
four distinct oils from as many different portions of the tree, 
namely, the needles, bark, oleoresin, and wood, making in all 
368 separate oils. This large field for investigation has been 
practically untouched. The author has examined 25 different 
volatile oils and oleoresins while approximately 26 others have 
received close investigation by various chemists. 
Previous Work 
The literature has been carefully examined in order to obtain 
references to the composition of the oils and oleoresins of Amer¬ 
ican species. In some cases the information is very meager be¬ 
ing limited to the yield of oil, saponification number or other 
constants. Certain species have been excluded from the follow¬ 
ing table since the articles relating to them gave no definite in¬ 
formation in regard to the constituents present. 
Needle Oils 
Red spruce ( Picea rubens Sarg.) 1 
Black spruce ( Picea mariana Mill.) 2 
White spruce ( Picea canadensis Mill.) 1 
Hemlock (Tsuga canadensis Linn.) 3 
Balsam fir (Abies balsamea Linn.) 4 
Tamarack ( Larix americana Mich.) 2 
White cedar (Thuja OccidentaUs Linn.) 5 
1 Hanson and Babcock, Jour. Am. Chem. Soc. 28 (1906) 1198. 
2 Kremers, Pharm. Rund. 13 (1895) 135; Hanson and Babcock, Jour. Am. 
Chem. Soc. 28 (1906) 1198; Schimmel & Co., Ber. Oct. (1897) 25. 
8 Hunkel, Pharm. Rev. 14 (1896) 34; Bertram and Walbaum, Arch. d. 
Pharm. 231 (1893) 290; Power, “Descriptive Catalogue of Essential Oils,” 
p. 74; Hanson and Babcock, loc. cit.; Pancoast and Graham. Proc. Pa. 
Pharm. Ass. (1905) 184; Schimmel and Co. Ber. Oct. (1894) 21, Oct. (1897) 
25. 
4 Hunkel, Am. Jour. Pharm. 67 (1895) 9. 
6 Wallach, Annalen 272 (1892) 99; Jahns, Arch. d. Pharm. 221 (1883) 
748; Ayer, Oil, Paint and Drug Rep. June 25, 1906, p. 17. 
